Generator of high-frequency currents.



i P. 0. PEDERSEN & V. POULS EN.

GENERATOR OF HIGH FREQUENCY CURRENTS.

, APPL'lCA]'l-0N FILED JAN-6,1913.

Lmmu Patented. Jan. 30,1917.

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PEDER OLUF PEDERSEN AND VATIDEMAR POULSEN, 0F FREDERIKSBERG, DENMK, ASSIGNORS TO FEDERAL TELEGRAPH COMPANY, A. CORPORATION OF CALIFORNIA.

GENERATOR OF HIGH-FREQUENCY CURRENTS.

Application filed January 6,

To all whom it may concern:

Be it known that we, PEDER OLUF PEDER- SEN and VALDEMAR PoULsEN, subjects of the King of Denmark, residing at Frederiksberg, Denmark, have invented certain new and useful Improvements in Generators of High-Frequency Currents, of which the fol- I lowing is a full, clear, and exact description.

Most generators of the are or spark type for currents of a high frequency have the peculiarity that under given circumstances,

thus for a given wavelength, feeding tension, damping, etc., they are only able to yield up to a certain high frequency effect, and this limit is often loWer than desirable. It has been attempted to overcome this difficulty by use of a plurality of generators arranged in series. This is possible in cases in which the high frequency circuit is of considerable resistance, the high frequency currents in this case having only a proportionately low intensity so that no drawbacks of any great importance appear by causing the high frequency currents to pass through all of the generators. But it is quite different when the high frequency circuit must necessarily have a low resistance. This is for instance the case in large stations for radio telegraphy and telephony working with great wave -lengths and therefore having a comparatively small resistance of radiation. In such cases, to obtain a suificient radiation, it is necessary to work with very strong high frequency currents. If it is here necessary to distribute the high frequency energy over a plurality of generators, a connection in series of these generators will be disadvantageous, as the strong high frequency currents will decrease the efliciency of the generators. A connection in multiple, however, will be highly desirable. The diificulty is found in causing the separate high frequency generators to cooperate in the right manner, whether those generators comprise arcs, spark gaps or the like. If the question is for instance of a Poulsen generator for continuous oscillations, provisions must in the first place be taken to make all of the generators work in the same phase. Even if the frequency was exactly the same,'it would be necessary to take special measures in order to secure the correct coincidence of phase. In causing all of the generators to work in parallel in the same circuit of vibrations,

Specification of Letters Patent.

Patented Jan. so, near.

1913. Serial No. 740,542.

another difficulty arises, for instance in the Poulsen generator, which has the peculiarity that the apparent resistance of the generator decreases when the intensity of the current increases. If therefore for some reason or other an unequal distribution of the high frequency current occurs, a tendency will be present to a continuous increasing of the said inequality, so that finally the greater part of the current will fall to one of the generators whereby it becomes less effective, while the other generator eventually becomes .currentless, and the aim of the connection in parallel will thus not be attained. Therefore measures must be taken for securing the equal distribution of the high frequency currents over all of the generators.

The present invention will be fully described by reference to the annexeddrawing showing schematically an embodiment of the invention, by which a uniform distribution of the high frequency energy over all of the generators can be obtained. In the figure only two generators are shown, but, as a matter of course, three or more can be used if wanted without departing from the spirit of the invention.

a and 1) indicate feeding terminals, 0 and d two Poulsen generators, e and f reducing rheostats, g and i2, reaction coils, 7s, m, n, 0 and p condensers, and g the self induction of the vibration circuit. This latter consists as it will be seen, of the self induction coil 9, the condenser 70 and the two parallel circuits comprising: the condenser is, the generator 0 and the condenser 91.; and the condenser m, the generator d and the condenser 0, respectively. The capacity of the condensers it, 'n, m and 0 (which will most frequently have the same value) -must for two reasons be rather small; firstly they will contribute to forcing the high frequency currents running in the circuit of vibration to distribute themselves more evenly over the generators the smaller their capacity is, and secondly the tendency of high frequency currents arising in the circuit formed by the condenser is, the generator 0, the condensers 'n. and 0, the generator d and the condenser am, will be the smaller the smaller the capacity of the condensers is. This is a circumstance of very great importance. If the condensers k, n, 0 and m are too large, independent high frequency currents will arise in the above densers are.

According to the invention self induction coils 'v, w, y and z are inserted in connection with the condensers. k, m, n and 0. It will especially often be-advisable to insert coils like 3 and 2 connected and arranged in such a manner that an increasing current in one coil, for instance 3 will tend to induce an increasingcurrent in the other coil 2, the direction of the current for the two coils being presumed to be positive from the connection point of the coils toward the condensers n and 0 respectively. Such an arrangement can greatly contribute to lessen the difi'erence of phase between the ignition of the two arcs.

Such coils can also be of use in other ways.

Having now described our invention what we claim and desire tosecure by Letters Patent of U. S. A. is:

In a system for generating high frequency currents, the combination of a feeding circuit, a plurality of generators connected in parallel in said circuit, a circuit of oscillation in which said generators are also connected in parallel, a plurality of condensers at least one in eachbranch of the divided portion of the said oscillation circuit and a plurality of self-induction coils, at least one in each branch of the divided portion of the oscillation circuit, the branches being inductively related to each other. I

In witness whereof, We have "subscribed our signatures, in the presence nesses.

PEDER OLUF PEDERSEN. VALDEMAR POULSEN.

Witnesses: CECIL V. ScHo'rT, FIGGQ BLAUE.

of two wit- 

